Audio Denoising Coprocessor Based on RISC-V Custom Instruction Set Extension

As a typical active noise control algorithm, FxLMS is widely used in the field of audio denoising. In this paper, an audio denoising coprocessor based on RISC-V custom instruction set extension was designed, and the idea of software and hardware co-design was adopted; based on the traditional pure-hardware implementation, the accelerator optimization design was carried out, and the accelerator was connected to RISC- V core in the form of coprocessor. Meanwhile, the corresponding custom instructions were designed, the compiling environment was established, and the library function of coprocessor acceleration instructions was established by embedded inline assembly. Finally, the ANC system was built and tested based on E203-SoC, and the test data was collected by audio analyzer. The results showed that the audio denoising algorithm could be realized by combining heterogeneous SoC with hardware accelerator, and the denoising effect was about 8dB. The number of instructions consumed by testing custom instructions for specific operations was reduced by about 60%, and the operation acceleration effect was significant.